Filament slipping in hobbed bolt

Hi.

I cant get an uniform extrusion because the filament keeps slipping in the hobbed bolt, damaging it and keeping it from extruding.

What are the common reasons for this?

I am printing ABS at several temps (220-250°).

The Z_Steps is correct. 100mm extrudes 100mm ±1mm. Without the nozzle, of course.

What could it be? Any advice is kindly appreciated.

Thanks

Do you have a photograph of your bolt?

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hi. the hobbed bolt itself is perfect.

i have tested with 3 different bolts already. Doesnt seem to be a hobbed bolt issue. I will take a photo in few minutes. meanwhile, what else could it be?

What hotend are you using?

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hi. I am using g3d buda-style.

its this one: [gadgets3d.com]

when i try to extrude it hot and with nozzle, it stops extruding after a few mm comes out.

what could it be?

CharlieSteurbaut Wrote:
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> Do you have a photograph of your bolt?


and here is the hobbed bolt i am using at the moment:

[www.dropbox.com]

That bolt is not so good this can be the problem.

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I have tested 3 bolts. I have them all. Here is a photo of the other 2:

[www.dropbox.com]

It extrudes perfectly well. I believe there could be another reason for the filament to ocasionally block on the nozzle, and that causes the slipping

Thats what i need to find out. Why does this happen with .04 and 0.5mm nozzle.

well, what else could it be other than the bolt?

Hard to tell. The hottend is clotched up probably. Is it mounted correctly.

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yes, i believe it is.

i put both the nozzles on acetone today for 24 hours for a complete cleaning. Will see if this helps.


I found on google search that a M303 command should auto adjust PID. But it does not give constant results. I run test 3 times, and i get 3 different results. How to get accurate values to put on marlin configuration?


And here is a test video extruding white abs at 240°:

[www.dropbox.com]

about 20 seconds of video, the filament blocked, and i had to help extruding with my hand.

You can se a red mark on the filament. Thats a 100mm mark i wanted to extrude, and it only extruded about 40mm.

I am sure that without the nozzle or anything blocking the filament, 100mm extruding is 100mm ±1mm. So thats pretty accurate. This means Z steps value is correct. But when extruding it hot and with the nozzle, only extruded about 40mm. That really seems to mean that something is blocking the filament.

Any suggestions?

Edited 1 time(s). Last edit at 06/29/2013 10:35AM by Crux.

sorry. here is the correct link for the video: [www.dropbox.com]

just had a look at the video.

Few things to try.

1. Check idler tension (might need to go tighter as pressure builds up in the hotend will be harder to push)

2. The extrusion width seems quite thick to me. Double check your Extruder Steps per mm. (Remember if you are using eeprom the firmware settings in arudino software mean nothing. you have to set using commands and then use the save command.) (Guide here [richrap.blogspot.co.uk])

3. Double check you are using the correct temp settings in marlin (setting depends on your hotend)

4. Try extruding slower see if this helps. (i normally test at 60mm/sec)

5. Have you checked your stepper drivers? (if using pololus you may need to turn up the power)

hope something here gets it working

Thank you for the reply. I will try those things today.

According to your suggestions:

1 - It is a lot tight at the moment. And it extrudes perfect without the nozzle.
2 - the extruder steps per mm (without nozzle) currently extrudes the correct measure. That link you posted is supposed to extrude with or without nozzle?
3 - could you be specific on temp settings? I didn't understand that.
4 - 60 mm/min that's the speed i usually test it, to make 1 mm/sec
5 - no. i didn't. will try that. In this pic you mean to increase "reference voltage", right?

thanks for all the replies.

Enlightx Wrote:
-------------------------------------------------------
> just had a look at the video.
>
> Few things to try.
>
> 1. Check idler tension (might need to go tighter
> as pressure builds up in the hotend will be harder
> to push)
>
> 2. The extrusion width seems quite thick to me.
> Double check your Extruder Steps per mm. (Remember
> if you are using eeprom the firmware settings in
> arudino software mean nothing. you have to set
> using commands and then use the save command.)
> (Guide here
> [richrap.blogspot.co.uk]
> cer-part-1-settings-and.html)
>
> 3. Double check you are using the correct temp
> settings in marlin (setting depends on your
> hotend)
>
> 4. Try extruding slower see if this helps. (i
> normally test at 60mm/sec)
>
> 5. Have you checked your stepper drivers? (if
> using pololus you may need to turn up the power)
>
> hope something here gets it working

Crux, as you've seen, this could be a lot of things.

One thing you might try to narrow it down is to remove the hotend from your extruder block, and measure the amount of filament that you get from a 100mm "extrusion."

If you get 100mm, you have an issue with pressure or clogging of the extruder, and the issue is stepper losing steps due to pressure, too cool a temperature, or an outright clog.

If you get less than 100mm, you have an issue with an incorrectly pressured idler (probably too tight), or stepper losing steps, or too much friction moving your gears (broken bearing?), or some such.

You might also run this test at different speeds, and see if this matters, as EnlightX suggests.

Good luck!

thank you for the reply.

as told before, without the hotend it extrudes perfect. 100mm extrusion is correct.

what could it be knowing 100% sure that without the hotend, extrusion is correct. But with the hotend, it extrudes less than 50% of whats supposed to extrude

Opinions are appreciated. Thanks.



Karmavore Wrote:
-------------------------------------------------------
> Crux, as you've seen, this could be a lot of
> things.
>
> One thing you might try to narrow it down is to
> remove the hotend from your extruder block, and
> measure the amount of filament that you get from a
> 100mm "extrusion."
>
> If you get 100mm, you have an issue with pressure
> or clogging of the extruder, and the issue is
> stepper losing steps due to pressure, too cool a
> temperature, or an outright clog.
>
> If you get less than 100mm, you have an issue with
> an incorrectly pressured idler (probably too
> tight), or stepper losing steps, or too much
> friction moving your gears (broken bearing?), or
> some such.
>
> You might also run this test at different speeds,
> and see if this matters, as EnlightX suggests.
>
> Good luck!

Remove your idler and try pushing the filament in by hand. A good hot end should be easy to extrude by hand. If it takes a lot of effort then either your temperature is to cold or for some reason your nozzle is clogging. I have one hot end that takes almost no effort at all to push filament through, others take a bit of pushing but not much.

If it is definately slipping on the hobbed bolt and not stepper/pinion then i would be cranking the bejeeeses out of the idler untill i got the motor stalled and backing off from there. I've heard having tension too tight can deform filament but i haven't been able to acheive this with my grooved idler.

I don't have allot of experience, but allot of opinions.

Hello,

Just a newbie stupid suggestion,

I noticed you have a fan in your video pointing towards the upper end of the hot end. Is the fan working (I'm unsure)?

Here's what the website says under "Kit includes":

Quote

- Fan Cooler (for cooling upper part of hotend for PLA printing)

Maybe the fan should not be run when extruding ABS?

Or maybe it's a faulty hotend?

BTW the G3D hotend is supposed to be a Budaschnozzle clone, but a Lulzbot Budaschnozzle does not need a fan to cool it either for ABS or PLA (I have a v1.1 but I have yet to print PLA with it).

Edited 1 time(s). Last edit at 06/30/2013 06:48PM by NormandC.